High pixel density structures and methods of making

Abstract

Methods of making high-pixel-density LED structures are described. The methods may include forming a backplane substrate and a LED substrate. The backplane substrate and the LED substrate may be bonded together, and the bonded substrates may include an array of LED pixels. Each of the LED pixels may include a group of isolated subpixels. A quantum dot layer may be formed on at least one of the isolated subpixels in each of the LED pixels. The methods may further include repairing at least one defective LED pixel by forming a replacement quantum dot layer on a quantum-dot-layer-free subpixel in the defective LED pixel. The methods may also include forming a UV barrier layer on the array of LED pixels after the repairing of the at least one defective LED pixel.

1 . A semiconductor processing method comprising:
 forming a backplane substrate and a LED substrate;   bonding the backplane substrate to the LED substrate, wherein the bonded substrates comprise an array of LED pixels, and wherein each of the LED pixels comprise a group of isolated subpixels;   forming a quantum dot layer on at least one of the isolated subpixels in each of the LED pixels;   repairing at least one defective LED pixel by forming a replacement quantum dot layer on a quantum-dot-layer-free subpixel in the defective LED pixel; and   forming a UV barrier layer on the array of LED pixels after the repairing of the at least one defective LED pixel.   
     
     
         2 . The semiconductor processing method of  claim 1 , wherein each of the LED subpixels comprises a gallium-and-nitrogen-containing light-emitting-diode structure operable to emit a first-wavelength light characterized by a wavelength less than or about 400 nm. 
     
     
         3 . The semiconductor processing method of  claim 2 , wherein the quantum dot layer is operable to absorb the first-wavelength light emitted from the gallium-and-nitrogen containing light-emitting diode structure and emit a second-wavelength light characterized by a longer wavelength than the first-wavelength light. 
     
     
         4 . The semiconductor processing method of  claim 1 , wherein the replacement quantum dot layer is operable to emit light at a same wavelength as a quantum dot layer formed on a non-operating subpixel in the defective LED pixel. 
     
     
         5 . The semiconductor processing method of  claim 1 , wherein unrepaired LED pixels comprise a quantum-dot-layer-free subpixel after formation of the UV barrier layer on the array of LED pixels. 
     
     
         6 . The semiconductor processing method of  claim 1 , wherein the array of LED pixels has a pixel density of greater than or about 1000 pixels per inch. 
     
     
         7 . The semiconductor processing method of  claim 1 , wherein a longest dimension of each of the isolated subpixels is less than or about 10 μm. 
     
     
         8 . The semiconductor processing method of  claim 1 , wherein the method further comprises forming a microlens on at least one of the subpixels in each of the LED pixels. 
     
     
         9 . A semiconductor processing method comprising:
 forming a backplane substrate and a LED substrate;   bonding the backplane substrate to the LED substrate, wherein the bonded substrates comprise an array of LED pixels, and wherein each of the LED pixels comprises at least four isolated subpixels;   forming quantum dot layers on at least three of the isolated subpixels in each of the LED pixels, wherein each of the quantum dot layers is operable to emit visible light at a different wavelength than the other quantum dot layers in the LED pixel; and   forming a UV barrier layer on the array of LED pixels, wherein at least a portion of the LED pixels comprises at least one quantum-dot-layer-free subpixel after the formation of the UV barrier layer.   
     
     
         10 . The semiconductor processing method of  claim 9 , wherein a pixel isolation structure is formed in the LED substrate before the LED substrate is bonded to the backplane substrate. 
     
     
         11 . The semiconductor processing method of  claim 9 , wherein a pixel isolation structure is formed in the bonded substrates after the LED substrate is bonded to the backplane substrate. 
     
     
         12 . The semiconductor processing method of  claim 9 , wherein an LED structure is formed into the LED substrate before the LED substrate is bonded to the backplane substrate. 
     
     
         13 . The semiconductor processing method of  claim 9 , wherein an LED structure is formed in the bonded substrates after the LED substrate is bonded to the backplane substrate. 
     
     
         14 . The semiconductor processing method of  claim 9 , wherein an additional backplane substrate is bonded to the bonded substrates on an exposed surface of the LED substrate. 
     
     
         15 . A semiconductor structure comprising:
 a backplane layer;   an array of LED pixels in contact with the backplane layer; and   a UV barrier layer on the array of LED pixels,
 wherein each of the LED pixels comprises at least four isolated subpixels, 
 at least three of the isolated subpixels comprise a quantum dot layer, and 
 at least a portion of the LED pixels comprises a subpixel that is quantum-dot-layer-free. 
   
     
     
         16 . The semiconductor structure of  claim 15 , wherein the backplane layer comprises a silicon-containing layer with CMOS devices in electrical contact with each of the isolated subpixels in each of the LED pixels. 
     
     
         17 . The semiconductor structure of  claim 15 , wherein the structure further comprises pixel isolation structures between each of the subpixels in each of the LED pixels, wherein the pixel isolation structures prevent light emitted from one of the subpixels from being absorbed by an adjacent subpixel. 
     
     
         18 . The semiconductor structure of  claim 15 , wherein each of the subpixels comprises a gallium-and-nitrogen-containing light-emitting diode structure. 
     
     
         19 . The semiconductor structure of  claim 15 , wherein at least one of the subpixels in each of the LED pixels further comprises a microlens in contact with the UV barrier layer. 
     
     
         20 . The semiconductor structure of  claim 15 , wherein the semiconductor structure is incorporated into a LED display for a virtual reality headset or augmented reality glasses.